#include <gst/gst.h>

int main(int argc, char *argv[]) {
  GstElement *pipeline, *source, *sink;
  GstBus *bus;
  GstMessage *msg;
  GstStateChangeReturn ret;

  gst_init(&argc, &argv);
  source = gst_element_factory_make("videotestsrc", "source");
  sink = gst_element_factory_make("autovideosink", "sink");

  pipeline = gst_pipeline_new("test-pipeline");
  if (!pipeline || !source || !sink) {
    g_printerr("Not all elements could be created.\n");
    return -1;
  }

  gst_bin_add_many(GST_BIN(pipeline), source, sink, NULL);
  if (gst_element_link(source, sink) != TRUE) {
    g_printerr("Elements could not be linked.\n");
    gst_object_unref(pipeline);
    return -1;
  }

  g_object_set(source, "pattern", 24, NULL);
  ret = gst_element_set_state(pipeline, GST_STATE_PLAYING);
  if (ret == GST_STATE_CHANGE_FAILURE) {
    g_printerr("Unable to set the pipeline to the playing state.\n");
    gst_object_unref(pipeline);
    return -1;
  }

  bus = gst_element_get_bus(pipeline);
  msg = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_ERROR | GST_MESSAGE_EOS);
  if (msg != NULL) {
    GError *err;
    gchar *debug_info;

    switch (GST_MESSAGE_TYPE(msg)) {
        case GST_MESSAGE_ERROR:
            gst_message_parse_error(msg, &err, &debug_info);
            g_printerr("Error received from element %s: %s\n", GST_OBJECT_NAME(msg->src), err->message);
            g_printerr("Debugging information: %s\n", debug_info ? debug_info : "none");
            g_clear_error(&err);
            g_free(debug_info);
            break;
        case GST_MESSAGE_EOS:
            g_print("End-of-stream reached.\n");
            break;
        default:
            g_printerr("Unexpected message received.\n");
            break;
    }
    gst_message_unref(msg);
  }

  //释放资源
  gst_object_unref(bus);
  gst_element_set_state(pipeline, GST_STATE_NULL);
  gst_object_unref(pipeline);
  return 0;
}
